1. Field of the Invention
The present invention relates to Fibre Channel network systems, and more particularly, to Inter-Fabric routing.
2. Background of the Invention
Fibre Channel is a set of American National Standard Institute (ANSI) standards, which provide a serial transmission protocol for storage and network protocols such as HIPPI, SCSI, IP, ATM and others. Fibre Channel provides an input/output interface to meet the requirements of both channel and network users.
Fibre Channel supports three different topologies: point-to-point, arbitrated loop and Fibre Channel Fabric. The point-to-point topology attaches two devices directly. The arbitrated loop topology attaches devices in a loop. The Fibre Channel Fabric topology attaches host systems directly to a Fabric, which are then connected to multiple devices. The Fibre Channel Fabric topology allows several media types to be interconnected.
Fibre Channel Fabric devices include a node port or “N_Port” that manages Fabric connections. The N_port establishes a connection to a Fabric element (e.g., a switch) having a Fabric port or “F_port”.
A Fibre Channel switch is a multi-port device where each port manages a point-to-point connection between itself and its attached system. Each port can be attached to a server, peripheral, I/O subsystem, bridge, hub, router, or even another switch. A switch receives messages from one port and routes it to another port.
Most Fibre Channel SANs are currently used as “SAN Islands”. The term island as used herein means an isolated fully contained SAN. The use of SAN islands has been common because switch suppliers have forced limits on SAN size and Information Technology managers have been reluctant to build larger SANs due to concerns about fault containment.
Inter-Fabric routing is an emerging concept in which SAN islands operate independently but can access devices among themselves using Inter-SAN (or Inter Fabric) routers. New header types are being proposed to facilitate Inter-Fabric routing. One disadvantage of this approach is that switch devices have to accommodate new header types, new Fabric routing protocols and extensions.
Therefore, there is a need for a method and system that can accommodate Inter-Fabric routing under current Fibre Channel protocol without having to rely on new headers, extensions and protocol changes.